# ERRATUM SHEET for the 2009 IMPERIAL COUNTY STATE IMPLEMENTATION PLAN FOR PARTICULATE MATTER LESS THAN 10 MICRONS IN AERODYNAMIC DIAMETER DRAFT FINAL

PAGE DESCRIPTION ORIGINAL CHANGE iv 4.2.3 reference page changed 4-6 4-7 4.2.5 reference page changed 4-7 4-8 4.3 reference page changed 4-8 4-9

v Appendix III.B title changed "Discussion of" removed. Discussion of Windblown Dust Emissions from Vacant Lands Windblown Dust Emissions from Vacant Lands

3-2 Second paragraph added

after ending of beginning of page. Specifically after "are reported in Table3.1. Footnotewas added changing all the numerical sequence of the footnotes throughout the document. See below We note thatthe model assumptions used to generatethe emission estimates of Table 3.1 did not evaluate the impact of off-road vehicular activities on the soil stability and emission characteristic profiles. Consequently, the level of additional emissions resulting from anthropogenic disturbance of vacant lands in Imperial County was assessed (in a conservative manner as documented in Appendix III.B) and incorporated in the present SIP Emission Inventory. The corresponding annual average level of additional PM10 emissions from open areas is 12.2 tpd (Table III.B.4 of Appendix III.B). Last sentence prior to Table 3.1 had text removed. Furtherdiscussion ofwindblown dustemissions from vacant lands, including estimation of upper bounds for the anthropogenic contribution to these emissions, is given in Appendix III.B. Further discussion of windblown dust emissions from vacant lands is given in Appendix III.B.

Table 3.1 was formatted no substance change A new footnote was added with the added paragraph. This changed the numerical sequence of all the footnotes within the document. No footnotes were deleted. [27]As noted in Appendix III.B, this estimate is conservative and the actual number is likely to be smaller. Winter and
summer contributions were calculated using the winter/summer temporal profile derived from the results of the windblown dust model for contributing sources (i.e., Shrubland/Grassland, Dunes, and other barren lands, see Table III.B.4 ofAppendix III.B). Thus, thewinter (181 days from November to April) and summer (184 days from May to October) emissions were 177.34/157.34 = 112.7% and 137.66/157.34 = 87.5% of the annual average, respectively. Footnotes numerically off 27 thru 31 28 thru 32

# ERRATUM SHEET for the 2009 IMPERIAL COUNTY STATE IMPLEMENTATION PLAN FOR PARTICULATE MATTER LESS THAN 10 MICRONS IN AERODYNAMIC DIAMETER DRAFT FINAL

PAGE DESCRIPTION ORIGINAL CHANGE
3-4 Windblown Dust Annual

Average 200.47 212.67

Windblown Dust Winter Average 210.03 223.79

Windblown Dust Summer Average 191.27 201.95
Open Areas -Othersb Annual Average 157.34 169.54

Open Areas -Othersb Winter Average 177.34 191.09

Open Areas -OthersbSummer Average 137.66 148.34
Total Annual Average 281 293 Total Winter Average 269 282 Total Summer Average 293 304 Table footnote added the sentence Reported emissions also included the conservativelyestimated contributions due to soil disturbance caused by off-road vehicle usage. Table 3.3 PM10Emission Inventory for Imperial County in Baseline Year 2005a(tpd)

# ERRATUM SHEET for the 2009 IMPERIAL COUNTY STATE IMPLEMENTATION PLAN FOR PARTICULATE MATTER LESS THAN 10 MICRONS IN AERODYNAMIC DIAMETER DRAFT FINAL

PAGE DESCRIPTION ORIGINAL CHANGE
3-4 Table footnote removed the

language An analysis of worst case upper estimates of potential increases in emissions from these lands due to off-highway vehicle (OHV) usewasconducted. Theworstcaseestimate is based on assuming the most emissive soil conditions rather than available soil condition information. Based on that analysis, additional annual average emissions from lands impacted by OHV use range from negligible (limited impacts due to either acreage of land disturbed or potentil degreee of increased emissivity) up to a worst-case estimate of 13.9 tpd (Table III.B.4). Of that 13.9 tpd worstcase estimate, 13.8 tpd is related OHV use on designated OHV use areas that are subject to BLM and state land requirements and 0.1 tpd istheworst-case estimate of OHV
use on undesignated areas. Based on observations, the increase is most likelyconsiderablylessthan theworst-case estimate. 3-5 Windblown: 2006 200.46 212.66

Windblown: 2007 200.46 212.66 Windblown: 2008 200.44 212.64 Windblown: 2009 200.44 212.64 Windblown: 210 200.43 212.63 Open Areas -Othersb2006 157.34 169.54 Open Areas -Othersb2007 157.34 169.54 Open Areas -Othersb2008 157.34 169.54 Open Areas -Othersb2009 157.34 169.54 Open Areas -Othersb2010 157.34 169.54 Total 2006 282 294 Total 2007 282 294 Total 2008 282 294 Total 2009 282 294 Total 2010 282 294 Table 3.4 Imperial County PM10Emission Inventoryain 2006-2010 (tpd)

# ERRATUM SHEET for the 2009 IMPERIAL COUNTY STATE IMPLEMENTATION PLAN FOR PARTICULATE MATTER LESS THAN 10 MICRONS IN AERODYNAMIC DIAMETER DRAFT FINAL

PAGE DESCRIPTION ORIGINAL CHANGE
3-5 Table footnote added the

sentence Reported emissions also included the conservativelyestimated contributions due to soil disturbance caused by off-road vehicle usage. Table footnote removed the language An analysis of worst case upper estimates of potential increases in emissions from these lands due to off-highway vehicle (OHV) usewasconducted. Theworstcaseestimate is based on assuming the most emissive soil conditions rather than available soil condition information. Based on that analysis, additional annual average emissions from lands impacted by OHV use range from negligible (limited impacts due to either acreage of land disturbed or potentil degreee of increased emissivity) up to a worst-case estimate of 13.9 tpd (Table III.B.4). Of that 13.9 tpd worstcase estimate, 13.8 tpd is related OHV use on designated OHV use areas that are subject to BLM and state land requirements and 0.1 tpd istheworst-case estimate of OHV
use on undesignated areas. Based on observations, the increase is most likelyconsiderablylessthan theworst-case estimate. 3-6 thru end of document Footnotes numerically off 32 thru 106 33 thru 107

4-5 804 (Open Aeas): Emissions

(tpd) 157.35 169.55

804 (Open Aeas): Reductions (tpd) 1.11 1.20

Other Open AreasbEmissions (tpd) 157.34 169.54
Total Emissions (tpd) 223 235 Total Reductions (tpd) 16.03 16.12

Table 4.1 Imperial County Regulation VIII Emission Reduction Summary (Based on the 2005 Annual Average Inventory)a

Table 3.4 Imperial County PM10Emission Inventoryain 2006-2010 (tpd) Continued

# ERRATUM SHEET for the 2009 IMPERIAL COUNTY STATE IMPLEMENTATION PLAN FOR PARTICULATE MATTER LESS THAN 10 MICRONS IN AERODYNAMIC DIAMETER DRAFT FINAL

PAGE DESCRIPTION ORIGINAL CHANGE
4-5 Table footnote b removed the

language . (see Table 3.1). As noted earlier (see footnotes of Table 3.3 and 3.4), the annual average emissions from this category, when calculated using assumptions of higher surface disturbance related to the impact of Off-Highway Vehicle usage, may be up to 13.9 tpd higher. Table 4.1 Imperial County Regulation VIII Emission Reduction Summary (Based on the 2005 Annual Average Inventory)a(Continued)

# ERRATUM SHEET for the Appendix III.A

PAGE DESCRIPTION ORIGINAL CHANGE III-4 Section III.6. Third sentence

changed. Theword "Also" has been removed Also, the results of the revised windblown dust study (see section III.5) were also used to develop revised annual and seasonal emission estimates for open areas (i.e., grasslands, dunes, barren lands).11 The results of the revised windblown dust study (see section III.5) werealso usedtodevelop revised annual and seasonal emission estimates for open areas (i.e., grasslands, dunes, barren lands).11 Section III.6. The following sentence was inserted after the end of the third paragraph sentence. Finally, additional PM10 emissions due to disturbance of soils as a result of off-road vehicle usage on Imperial County vacant lands were calculated as documented in Appendix III.B Section III.6 The final sentence in the paragraph has the following revisions. The revised emission factorand updated study resulted in a

~ 140% increase in PM10 emissions from this categories to 187.9tpd. The revised emission factor and updated studies resulted in a > 150% increase in PM10 emissions from these categories to 200.1 tpd III-5 Windblown Dust / Annual

Average 200.47 212.67

Windblown Dust / Winter Average 210.03 223.79

Windblown Dust / Summer Average 191.27 201.95
Open Areas-Othersb / Annual Average 157.34 169.54

Open Areas-Othersb / Winter Average 177.34 191.09

Open Areas-Othersb / Summer Average 137.66 148.34
Total / Annual Average 281 293 Total / Winter Average 269 282 Total / Summer Average 293 304 Table III.1 The following sentence was inserted after the end of the second sentence in footnote "B". Reported emissions also include the conservativelyestimated contributions dueto soil disturbances caused by off-road vehicle usage Table III.1 PM10Emission Inventory for Imperial County in Baseline Year 2005a(tpd)

# ERRATUM SHEET for the Appendix III.A

PAGE DESCRIPTION ORIGINAL CHANGE
III-5 Table III.1 The following

sentences were removed from footnote "B". An analysis of worst case upper estimates of potential increases in emissions from those lands due to off-highway vehicle (OHV) use was conducted. The worst-case estimate is based on assuming the most emissive soil conditions rather than available soil condition information. Based on thatanalysis, additional annual averageemissions from lands impacted by OHV use range from negligible (limited impacts due to either acreage of land disturbed or potential degree of increased emissivity) up to a worst-case estimate of 13.9 tpd (Table III.B.4) Of that 13.9 tpd worstcase estimate, 13.8tpd is related to OHV use on designated OHV use areas that are subject to BLM and state land requirements and 0.1 tpd is the worst-case estimated of OHV use on undesignated areas. Based on observations, the increase is most likelyconsiderably less than the worstcase estimate. III-6 Windblown: 2006 200.46 212.66

Windblown: 2007 200.46 212.66 Windblown: 2008 200.44 212.64 Windblown: 2009 200.44 212.64 Windblown: 2010 200.43 212.63 Open Areas-Othersb: 2006 157.34 169.54 Open Areas-Othersb: 2007 157.34 169.54 Open Areas-Othersb: 2008 157.34 169.54 Open Areas-Othersb: 2009 157.34 169.54 Open Areas-Othersb: 2010 157.34 169.54 Total: 2006 282 294 Total: 2007 282 294 Total: 2008 282 294 Total: 2009 282 294 Total: 2010 282 294 Table III.2 Imperial County PM10Annual-Average Emission Inventoryain 2006-2010 (tpd)

# ERRATUM SHEET for the Appendix III.A

PAGE DESCRIPTION ORIGINAL CHANGE
III-6 Table III.2 The following

sentence was inserted after the end of the second sentence in footnote "B". Reported emissions also include the conservativelyestimated contributions dueto soil disturbances caused by off-road vehicle usage

Table III.2 The following sentences were removed from footnote "B". An analysis of worst case upper estimates of potential increases in emissions from those lands due to off-highway vehicle (OHV) use was conducted. The worst-case estimate is based on assuming the most emissive soil conditions rather than available soil condition information. Based on thatanalysis, additional annual averageemissions from lands impacted by OHV use range from negligible (limited impacts due to either acreage of land disturbed or potential degree of increased emissivity) up to a worst-case estimate of 13.9 tpd (Table III.B.4) Of that 13.9 tpd worstcase estimate, 13.8tpd is related to OHV use on designated OHV use areas that are subject to BLM and state land requirements and 0.1 tpd is the worst-case estimated of OHV use on undesignated areas. Based on observations, the increase is most likelyconsiderably less than the worstcase estimate. III-7 Windblown: 2006 210.02 223.77

Windblown: 2007 210.02 223.77 Windblown: 2008 210.01 223.76 Windblown: 2009 210.01 223.76 Windblown: 2010 209.99 223.74 Open Areas-Othersb: 2006 177.34 191.09 Open Areas-Othersb: 2007 177.34 191.09 Open Areas-Othersb: 2008 177.34 191.09 Open Areas-Othersb: 2009 177.34 191.09 Open Areas-Othersb: 2010 177.34 191.09 Total: 2006 269 283 Total: 2007 270 283 Table III.3 Imperial County PM10Winter-Average Emission Inventoryain 2006-2010 (tpd)

# ERRATUM SHEET for the Appendix III.A

PAGE DESCRIPTION ORIGINAL CHANGE
III-7 Total: 2008 270 284

Total: 2009 270 284 Total: 2010 270 284 Table III.3 The following sentence was inserted after the end of the second sentence in footnote "B". Reported emissions also include the conservativelyestimated contributions dueto soil disturbances caused by off-road vehicle usage

Table III.3 The following sentences were removed from footnote "B". An analysis of worst case upper estimates of potential increases in emissions from those lands due to off-highway vehicle (OHV) use was conducted. The worst-case estimate is based on assuming the most emissive soil conditions rather than available soil condition information. Based on thatanalysis, additional annual averageemissions from lands impacted by OHV use range from negligible (limited impacts due to either acreage of land disturbed or potential degree of increased emissivity) up to a worst-case estimate of 13.9 tpd (Table III.B.4) Of that 13.9 tpd worstcase estimate, 13.8tpd is related to OHV use on designated OHV use areas that are subject to BLM and state land requirements and 0.1 tpd is the worst-case estimated of OHV use on undesignated areas. Based on observations, the increase is most likelyconsiderably less than the worstcase estimate. III-8 Windblown: 2006 190.89 201.93

Windblown: 2007 190.89 201.93 Windblown: 2008 190.88 201.92 Windblown: 2009 190.88 201.92 Windblown: 2010 190.87 201.91 Open Areas-Othersb: 2006 137.34 148.34 Open Areas-Othersb: 2007 137.34 148.34 Open Areas-Othersb: 2008 137.34 148.34 Open Areas-Othersb: 2009 137.34 148.34 Table III.4 Imperial County PM10Summer-Average Emission Inventoryain 2006-2010 (tpd)

# ERRATUM SHEET for the Appendix III.A

PAGE DESCRIPTION ORIGINAL CHANGE
III-8 Open Areas-Othersb: 2010 137.34 148.34

Total: 2006 294 305 Total: 2007 294 305 Total: 2008 294 305 Total: 2009 294 306 Total: 2010 294 305 Table III.4 The following sentence was inserted after the end of the second sentence in footnote "B". Reported emissions also include the conservativelyestimated contributions dueto soil disturbances caused by off-road vehicle usage

Table III.4 The following sentences were removed from footnote "B". An analysis of worst case upper estimates of potential increases in emissions from those lands due to off-highway vehicle (OHV) use was conducted. The worst-case estimate is based on assuming the most emissive soil conditions rather than available soil condition information. Based on thatanalysis, additional annual averageemissions from lands impacted by OHV use range from negligible (limited impacts due to either acreage of land disturbed or potential degree of increased emissivity) up to a worst-case estimate of 13.9 tpd (Table III.B.4) Of that 13.9 tpd worstcase estimate, 13.8tpd is related to OHV use on designated OHV use areas that are subject to BLM and state land requirements and 0.1 tpd is the worst-case estimated of OHV use on undesignated areas. Based on observations, the increase is most likelyconsiderably less than the worstcase estimate.

# ERRATUM SHEET for the Appendix III.B

PAGE DESCRIPTION ORIGINAL CHANGE COVER Removed the words

"DISCUSSION OF" from header throughout document Appendix III.B: Discussion ofWindblown Appendix III.B:Windblown

Removed the words "DISCUSSION OF" from title DISCUSSION OFWINDBLOWN DUST EMISSIONS FROM VACANT LANDS WINDBLOWN DUST EMISSIONS FROM VACANT LANDS III.B-i Removed and added wording This appendix provides additional information about windblown dust estimates from vacant lands, as calculated by the windblown dust model (ENVIRON, 2004 and later revisions). In addition, itconsidersthe possible impactofoffroad activity on the emission inventory for these areas (beyond assumptions already used in the modeling) by identifying those state and federal lands where off-road activities are allowed and calculating a "worst case" bound of potential additional anthropogenic emissions. This appendix provides additional information about windblown dustestimatesfrom vacant lands, as calculated by the windblown dust model (ENVIRON, 2004 and later revisions). In addition, it considers the impact ofoff-road activity on the emission inventory for these areas by identifying those state and federal lands where off-road activities are allowed and estimating the additional levels of emissions (relative to the estimates of Table 3.1 of the SIP document) that arise from these lands due to anthropogenic soil disturbance unaccounted for in prior modeling assumptions (see Section III.B.2ofthisappendix for details.)
III.B-3 Replaced words last sentence

under "Model Assumptions in Calculation of Imperial County Windblown PM10 Emissions Best Estimates Best estimates of windblown dust emissions in Imperial Countycalculated using the windblown dust model3 (Tables 3.1and 3.2of the SIP document)wereobtained asssuming: Best estimates of windblown dust emissions in Imperial Countycalculated using the windblown dust model3 (Table 3.1 of the SIP document)wasobtained asssuming:

III.B-4 Replaced words section

III.B.3 Title Possible Impact of Anthropogenic Disturbance of Vacant Lands Beyond Model Assumptions Estimated Impact of Anthropogenic Disturbance of Vacant Lands Beyond Model Assumptions First Bullet point added
comma Theanthropogeniccontribution should beestimated asthe incremental level of emissions relative to the native baseline, i.e., Second Bullet point changed do to does In some cases, this difference is zero. For instance, the sand dunes are fully unstable and have 0% vegetative canopy cover in the native state. Therefore, vehicle offroading on these lands do not alter any of the parameters that impact emissions, such as soil type, LULC, stability, or reservoi characteristics. In some cases, this difference is zero. For instance, the sand dunes are fully unstable and have 0% vegetative canopy cover in the native state. Therefore, vehicle offroading on these lands does not alter any of the parameters that impact emissions, such as soil type, LULC, stability, or reservoi characteristics.

# ERRATUM SHEET for the Appendix III.B

PAGE DESCRIPTION ORIGINAL CHANGE
III.B-4 Second paragraph second

sentence completely removed Therefore, in light of the uncertainty described above in the model estimates, there is insufficient information to suggest which refined assumptions (about soil characteristics for each disturbed and undisturbed vacant land in Imperial County) should be chosen to obtain more accurate emission estimates. Last paragraph was merged with the second paragraph and had language removed. Nevertheless, in responseto particularinterest inthe level of emissions from vacant lands that is due to off-road anthropogenic activity we conducted additional analyses to estimate conservative upper bounds of the incremental levels of windblown dust emissions... Nevertheless, in response to particular interest in the level of emissions from vacant lands that is due to off-road anthropogenic activity, and to establish a complete emissions inventory, we conducted additional analyses to estimate conservative estimates of the incremental levels of windblown dust emissions... III.B-5 Deleted words "Upper Bound"

from Title Conservative Upper Bound Estimates of Additionala PM10 Emissions Due to Off-Road Anthropogenic Disturbanceb of Federal and State Vacant Lands in Imperial County. Conservative Estimates of Additionala PM10 Emissions Due to Off-Road Anthropogenic Disturbanceb of Federal and State Vacant Lands in Imperial County. Wording changed on title heading of the third column Upper BoundEstimate of AdditionalaPM10Emissions (tpd) ConservativeEstimate of AdditionalaPM10Emissions (tpd)

BLM Open Areas Column three 7.5 5.8

BLM Open Areas Plaster City Column three 1.8 0.6

BLM Open Areas Superstition Mountains Column three 0.8 0.3

Total column three 13.8tpd ~12.1tpd Footnote a for table changed wording aRelative to windblown dust model results established in Section 3.1.1 ofthe SIP document and Section III.B.2 ofthis report. aRelative to windblown dust model results established in Section 3.1.1 of the SIP document and Section III.B.2 of thisappendix. Under the reasoning section third bullet point the percentage and wording was changed Anthropogenic disturbance of these lands can be expected to generate some level of instability. Based on information provided by BLM,4we assume here that up to 50% of these lands are disturbed by OHV usage. Using this assumption, extreme estimates of emissions may be obtained using the rate of emissions per acre... Anthropogenicdisturbanceofthese landscan beexpected to generate some level of instability. Based on information provided by BLM,4 we assume here that up to 16% of these lands are disturbed by OHV usage. Using this assumption, conservative estimates of emissions may be obtained using the rate of emissions per acre... Table III.B.3

# ERRATUM SHEET for the Appendix III.B

PAGE DESCRIPTION ORIGINAL CHANGE
III.B-5 Footnote 4 removed language

and added language 4Communication from Erin Dreyfuss to the ICAPCD July 2009 4Communication to the ICAPCD from the El Centro Field Office of the Bureau of Land Management, United States Department of the Interior,July22,2009 III.B-6 First paragraphs percentage

changed and wording changed results5obtained in this mannerare reported in Table III.B.3. This analysis is very conservative because (i) the assumption of50%disturbance is conservative.... results5 obtained in this manner are reported in Table III.B.3. This analysis is conservative because (i) the assumption of 16%disturbance is conservative.... Under the Sand Dunes section second bullet middle of the paragraph wording was added (Table III.B.1). If we apply the rate of PM10emissions.... (Table III.B.1). Information provided by the BLM (refer to footnote 4 above) indicates that approximately 50% of these lands are disturbed by OHV usage. If we applythe rate of PM10emissions.... Footnote 5 had percentage changes and total tpd changes towards end of footnote 5 ...areas are 50%x 1.3x 10-4tpd/acrex27x 103acres = 1.8 tpd for the Plaster City Open Area and 50% x 1.3 x 10-4

tpd/acre x 13 x 103 acres = 0.8 tpd for the Superstition Mountains Open Area. ...areas are 16% x 1.3 x 10-4 tpd/acre x 27 x 103 acres = 0.6tpd forthe PlasterCityOpen Area and 50% x 1.3x 10-
4 tpd/acre x 13 x 103 acres = 0.3 tpd for the Superstition Mountains Open Area. Last sentence calculation factor changed ...the Arroyo Salado area are 50%x0.4 tpdx200= 4 tpd... ...the Arroyo Salado area are 50%x0.4 tpdx20= 4 tpd...

III.B-7 Under III.B.4 Summary words

were removed and added as were amounts related to tpd. According to the foregoing analyses, a conservative upper bound of additional7 windblown PM10 emissions due to anthropogenic activities8 on Imperial Countyvacant lands is

< 14 tpd. (The actual number is likely to be considerably smaller, based on the nature of the conservative assumptions used in the above analysis.)... According to the foregoing analyses, a conservative estimate of additional7 windblown PM10 emissions due to anthropogenic activities8 on Imperial County vacant lands is < 12.2 tpd. (The actual number is likely to be smaller, based on the nature ofthe conservative assumptions used in the above analysis.)... III.B-8 Deleted words "Upper Bound"

from Title Summary Table of Modeled PM10 Emissions (Reported According to LULC) and Conservative Upper Bound Estimates of Additionala PM10 Emissions Resulting from Assumptions of More Severe Impacts to OHV Usage on Soils Disturbed by OHV Usage. Summary Table of Modeled PM10 Emissions (Reported According to LULC) and Conservative Upper Bound Estimates of Additionala PM10 Emissions Resulting from Assumptions of More Severe Impacts to OHV Usage on Soils Disturbed by OHV Usage. Wording changed on title heading of the third column Upper Bound of additonalc PM10 Emissions assuming more severe impacts ofOHV usage (tpd) Conservative EstimateofadditonalcPM10Emissions due to OHV usage (tpd) Desert-Other Designated for OHV usage third column rate changed 12.3d 11.0d Table III.B.4

# ERRATUM SHEET for the Appendix III.B

PAGE DESCRIPTION ORIGINAL CHANGE
III.B-8 Shrubland/Grassland

Designated for OHV usage third column rate changed 1.5f 1.1f

Total column three 13.9tpd 12.2tpd

# ERRATUM SHEET for the Appendix IV C

PAGE DESCRIPTION ORIGINAL CHANGE IV.C-2 Windblown: 2006 196.40 208.52

Windblown: 2007 196.34 208.45 Windblown: 2008 196.26 208.37 Windblown: 2009 196.19 208.3 Windblown: 2010 196.11 208.22 Open Areas-Othersb: 2006 156.24 168.35 Open Areas-Othersb: 2007 156.24 168.35 Open Areas-Othersb: 2008 156.24 168.35 Open Areas-Othersb: 2009 156.24 168.35 Open Areas-Othersb: 2010 156.24 168.35 Total: 2006 274 286 Total: 2007 273 285 Total: 2008 272 284 Total: 2009 272 284 Total: 2010 271 283 Table IV.C-2 The following sentence was inserted after the end of the second sentence in footnote "B". Reported emissions also include the conservativelyestimated contributions dueto soil disturbances caused by off-road vehicle usage Table IV.C-2 Imperial County PM10 "Grown and Controlled" Annual Average Emision Inventoryain 2006-2010 (tpd)

# ERRATUM SHEET for the Appendix IV C

PAGE DESCRIPTION ORIGINAL CHANGE Table IV.C-2 Imperial County PM10 "Grown and Controlled" Annual Average Emision Inventoryain 2006-2010 (tpd) IV.C-2 Table IV.C-2 The following

sentences were removed from footnote "B". An analysis of worst case upper estimates of potential increases in emissions from those lands due to off-highway vehicle (OHV) use was conducted. The worst-case estimate is based on assuming the most emissive soil conditions rather than available soil condition information. Based on thatanalysis, additional annual averageemissions from lands impacted by OHV use range from negligible (limited impacts due to either acreage of land disturbed or potential degree of increased emissivity) up to a worst-case estimate of 13.9 tpd (Table III.B.4) Of that 13.9 tpd worstcase estimate, 13.8tpd is related to OHV use on designated OHV use areas that are subject to BLM and state land requirements and 0.1 tpd is the worst-case estimated of OHV use on undesignated areas. Based on observations, the increase is most likelyconsiderably less than the worstcase estimate. IV.C-3 Windblown: 2006 205.86 219.51

Windblown: 2007 205.82 218.47 Windblown: 2008 205.77 218.42 Windblown: 2009 205.77 219.38 Windblown: 2010 205.67 219.33 Open Areas-Othersb: 2006 176.10 189.75 Open Areas-Othersb: 2007 176.10 189.75 Open Areas-Othersb: 2008 176.10 189.75 Open Areas-Othersb: 2009 176.10 189.75 Open Areas-Othersb: 2010 176.10 189.75 Total: 2006 262 275 Total: 2007 261 275 Total: 2008 261 274 Total: 2009 260 274 Total: 2010 260 273 Table IV.C-3 Imperial County PM10 "Grown and Controlled" Winter Average Emission Inventoryain 2006-2010 (tpd)

# ERRATUM SHEET for the Appendix IV C

PAGE DESCRIPTION ORIGINAL CHANGE Table IV.C-2 Imperial County PM10 "Grown and Controlled" Annual Average Emision Inventoryain 2006-2010 (tpd) IV.C-3 Table IV.C-3 The following

sentence was inserted after the end of the second sentence in footnote "B". Reported emissions also include the conservativelyestimated contributions dueto soil disturbances caused by off-road vehicle usage

Table IV.C-3 The following sentences were removed from footnote "B". An analysis of worst case upper estimates of potential increases in emissions from those lands due to off-highway vehicle (OHV) use was conducted. The worst-case estimate is based on assuming the most emissive soil conditions rather than available soil condition information. Based on thatanalysis, additional annual averageemissions from lands impacted by OHV use range from negligible (limited impacts due to either acreage of land disturbed or potential degree of increased emissivity) up to a worst-case estimate of 13.9 tpd (Table III.B.4) Of that 13.9 tpd worstcase estimate, 13.8tpd is related to OHV use on designated OHV use areas that are subject to BLM and state land requirements and 0.1 tpd is the worst-case estimated of OHV use on undesignated areas. Based on observations, the increase is most likelyconsiderably less than the worstcase estimate. IV.C-4 Windblown: 2006 186.95 197.79

Windblown: 2007 186.95 197.7 Windblown: 2008 186.75 197.59 Windblown: 2009 186.65 197.49 Windblown: 2010 186.55 197.39 Open Areas-Othersb: 2006 136.38 147.3 Open Areas-Othersb: 2007 136.38 147.3 Open Areas-Othersb: 2008 136.38 147.3 Open Areas-Othersb: 2009 136.38 147.3 Open Areas-Othersb: 2010 136.38 147.3 Total: 2006 286 297 Total: 2007 285 296 Table IV.C-4 Imperial County PM10 "Grown and Controlled" Summer Average Emission Inventorya in 2006-2010 (tpd)

# ERRATUM SHEET for the Appendix IV C

PAGE DESCRIPTION ORIGINAL CHANGE Table IV.C-2 Imperial County PM10 "Grown and Controlled" Annual Average Emision Inventoryain 2006-2010 (tpd) IV.C-4 Total: 2008 284 295

Total: 2009 283 294 Total: 2010 281 292 Table IV.C-4 The following sentence was inserted after the end of the second sentence in footnote "B". Reported emissions also include the conservativelyestimated contributions dueto soil disturbances caused by off-road vehicle usage

Table IV.C-4 The following sentences were removed from footnote "B". An analysis of worst case upper estimates of potential increases in emissions from those lands due to off-highway vehicle (OHV) use was conducted. The worst-case estimate is based on assuming the most emissive soil conditions rather than available soil condition information. Based on thatanalysis, additional annual averageemissions from lands impacted by OHV use range from negligible (limited impacts due to either acreage of land disturbed or potential degree of increased emissivity) up to a worst-case estimate of 13.9 tpd (Table III.B.4) Of that 13.9 tpd worstcase estimate, 13.8tpd is related to OHV use on designated OHV use areas that are subject to BLM and state land requirements and 0.1 tpd is the worst-case estimated of OHV use on undesignated areas. Based on observations, the increase is most likelyconsiderably less than the worstcase estimate.

# ERRATUM SHEET for the Appendix V

PAGE DESCRIPTION ORIGINAL CHANGE V-18 Windblown Dust Annual

Average (tpd) changed 200.47 212.67

Windblown Dust Open Areas

- Grasslands, Dunes, Barren Lands Annual Average (tpd) changed 157.34 169.54

Total Annual Average (tpd) changed 124 136

NOTE V-19 V-20 V-23 V-24 V-26 Windblown Dust Winter

Average (tpd) changed 210.03 223.79

Windblown Dust Open Areas

- Othersb Winter Average (tpd) changed 177.34 191.09 Version released for review had underlined words that were missed. There is no significance to the underlined words and should not be underlined. Table 14 Imperial County Winter PM10Emission Inventory (2005)a Table 13 PM10Emission Inventory for Imperial County in 2005

Version released for review had underlined words that were missed. There is no significance to the underlined words and should not be underlined. Version released for review had underlined words that were missed. There is no significance to the underlined words and should not be underlined. Version released for review had underlined words that were missed. There is no significance to the underlined words and should not be underlined. Version released for review had underlined words that were missed. There is no significance to the underlined words and should not be underlined.